U.S. patent application number 12/351491 was filed with the patent office on 2009-07-16 for method and apparatus for providing a positive pressure in the headspace of a plastic container.
This patent application is currently assigned to Ball Corporation. Invention is credited to Darren D. Livingston.
Application Number | 20090179032 12/351491 |
Document ID | / |
Family ID | 40849768 |
Filed Date | 2009-07-16 |
United States Patent
Application |
20090179032 |
Kind Code |
A1 |
Livingston; Darren D. |
July 16, 2009 |
Method and Apparatus for Providing A Positive Pressure in the
Headspace of a Plastic Container
Abstract
The present invention is directed to a method and apparatus for
accommodating the pressure decrease of the fluid in a hot-filled
plastic container.
Inventors: |
Livingston; Darren D.;
(Denver, CO) |
Correspondence
Address: |
SHERIDAN ROSS PC
1560 BROADWAY, SUITE 1200
DENVER
CO
80202
US
|
Assignee: |
Ball Corporation
Broomfield
CO
|
Family ID: |
40849768 |
Appl. No.: |
12/351491 |
Filed: |
January 9, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61020633 |
Jan 11, 2008 |
|
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61105241 |
Oct 14, 2008 |
|
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Current U.S.
Class: |
220/254.7 ;
220/254.8 |
Current CPC
Class: |
B65D 41/325 20130101;
B65D 41/34 20130101; B65D 79/005 20130101 |
Class at
Publication: |
220/254.7 ;
220/254.8 |
International
Class: |
B65D 51/24 20060101
B65D051/24 |
Claims
1. A closure cap adapted for selective interconnection to a neck of
a plastic container, comprising: a main panel with a
circumferential sidewall extending therefrom; at least one fin
extending from said main panel and operably spaced from said
sidewall, said at least open fin including an aperture to allow the
ingress and egress of ambient air; a diaphragm having a head with
an inner skirt extending therefrom that is interconnected, via a
convolution, to an outer skirt, said outer skirt interconnected to
an outwardly extending seal that is positioned between said
sidewall and said at least one fin; wherein when said closure cap
is tightened onto the neck of the plastic container, said seal is
engaged on an upper surface of the neck; and wherein said head of
said diaphragm from a first position substantially adjacent to said
main panel to a second extended position away from said main panel
when a fluid within the container is cooled a predetermined
amount.
2. The closure cap of claim 1, further comprising a catch ring
interconnected to said seal that is adapted to move between a free
end of said at least one fin and said main panel.
3. The closure cap of claim 1, further comprising a tamper evidence
band interconnected to said sidewall to indicate whether the
container seal has been compromised.
4. The closure cap of claim 1, further comprising a disk
interconnected to said head of said diaphragm, said disk having a
stiffness greater than said diaphragm.
5. The closure cap of claim 2, wherein said catch ring includes at
least one aperture that allows ambient air to pass from a space
between said sidewall and said neck to a chamber positioned above
said diaphragm by way of at least one aperture in said at least one
fin.
6. The closure cap of claim 1, wherein said at least one fin
includes an upper catch positioned adjacent to said main panel and
a lower catch positioned adjacent to said free end wherein prior to
positioning said cap onto said neck, said catch ring is engaged
onto said lower catch and subsequent to sealing said cap onto said
neck, said catch ring is engaged adjacent to said upper catch.
7. The closure cap of claim 1, wherein said at least one fin
comprises eight spaced fins wherein the spaces between adjacent
fins allows the ingress and egress of ambient air.
8. The closure cap of claim 1, wherein said diaphragm is comprised
of a non-permeable material;
9. A closure system adapted for selective interconnection to a neck
of a container, comprising: a main panel with a circumferential
outer wall extending therefrom; a pressure compensation means
associated with said cap which comprises a chamber positioned
between said main panel and said outer wall and which is in
communication with ambient air; wherein when said closure system is
tightened onto the neck of the container that is filled with a
fluid at a first temperature, said seal is engaged on an upper
surface of the neck; and wherein said pressure compensation means
expands in a direction toward said fluid when said fluid is at
second temperature.
10. The closure system of claim 9, further comprising an inner wall
extending from said main panel and spaced from said outer wall.
11. The closure system of claim 10 wherein said pressure
compensation means is a diaphragm having a head with an inner skirt
extending therefrom that is interconnected, via a convolution, to
an outer skirt, said outer skirt interconnected to an outwardly
extending seal that is positioned between said outer wall and said
inner wall.
12. The closure system of claim 11, wherein said first
configuration comprises said head of said diaphragm moves from a
first position adjacent to said main panel and said second
configuration comprises the head adjacent to the fluid.
13. The closure system of claim 10, further comprising a catch ring
interconnected to said seal that is adapted to move between a free
end of said inner wall and said main panel.
14. The closure system of claim 9, further comprising a tamper
evidence band interconnected to said outer wall.
15. The closure system of claim 11, further comprising a disk
interconnected to said head of said diaphragm, said disk having a
stiffness greater than said diaphragm.
16. The closure system of claim 13, wherein said catch ring
includes at least one space that allows gas to pass from a space
between said sidewall and said neck to the inside of the container
by way of at least one opening in said inner wall.
17. The closure cap of claim 13, wherein said inner wall includes
an upper catch positioned adjacent to said main panel and a lower
catch positioned adjacent to said free end wherein prior to
positioning said cap onto said neck, said catch ring is engaged
onto said lower catch and subsequent to sealing said cap onto said
neck, said catch ring is engaged adjacent to said upper catch.
18. The closure cap of claim 9, wherein said inner wall comprises a
plurality of spaced fins wherein the spaces between adjacent fins
allows the ingress and egress of gas.
19. A flexible beverage container and associated reclosable cap,
comprising: a container body having a neck interconnected to a
body, said body having a container sidewall, said container body
adapted to receive fluids of a first temperature; a closure cap
adapted for selective interconnection to said neck of the plastic
container, comprising: a main panel with a sidewall extending
therefrom; at least one fin extending from said main panel and
operably spaced from said sidewall; a diaphragm having a head with
an inner skirt extending therefrom that is interconnected, via a
convolution, to an outer skirt, said outer skirt interconnected to
an outwardly extending seal that is positioned between said
sidewall and said at least one fin; wherein when said closure cap
is tightened onto said seal is engaged on an upper surface of said
neck; and wherein said head of said diaphragm moves from a first
position adjacent to said main panel to a second position adjacent
to the fluid when the temperature of the fluid is reduced from the
first temperature to a lower second temperature.
20. The beverage container of claim 19, wherein said container body
is made of a rigid non-metallic material.
21. The beverage container of claim 19, further comprising a fluid
stored within said container body.
22. The beverage container of claim 19, wherein said container
sidewall is cylindrical and further comprising a label
interconnected to said container sidewall wherein said label
possess a radius of curvature generally equal to the radius of said
container sidewall.
23. The beverage container of claim 19, further comprising a catch
ring interconnected to said seal that is adapted to move between a
free end of said at least one fin and said main panel.
24. The beverage container of claim 19, further comprising a tamper
evidence band interconnected to said sidewall.
25. The beverage container of claim 19, further comprising a disk
interconnected to said head of said diaphragm, said disk having a
stiffness greater than said diaphragm.
26. The beverage container of claim 23, wherein said catch ring
includes at least one space that allows gas to pass from a space
between said sidewall and said neck to the inside of the container
by way of at least one opening in said at least one fin.
27. The beverage container of claim 23, wherein said at least one
fin includes an upper catch positioned adjacent to said main panel
and a lower catch positioned adjacent to said free end wherein
prior to positioning said cap onto said neck, said catch ring is
engaged onto said lower catch and subsequent to sealing said cap
onto said neck, said catch ring is engaged adjacent to said upper
catch.
28. The beverage container of claim 19, wherein said at least one
fin includes at least one opening that allows the ingress and
egress of gas.
29. The beverage container of claim 19, wherein said at least one
fin comprises eight spaced fins wherein the spaces between adjacent
fins allows the ingress and egress of gas.
30. The beverage container of claim 19, wherein pressure in the
headspace of the container is increased as the closure cap is
interconnected to the neck of the container.
Description
[0001] This application claims the benefit of pending Provisional
Patent Application Ser. No. 61/105,241, filed Oct. 14, 2008 and
pending Provisional Patent Application Ser. No. 61/020,633, filed
Jan. 11, 2008, the entire disclosures of each application being
incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a closure for an
associated container, and more specifically to a rotatable cap
closure with one or more sealing features for creating a positive
pressure or accommodating a pressure drop in a plastic container
associated with the occurrence of a vacuum, thereby generally
preventing the deformation of the container.
BACKGROUND OF THE INVENTION
[0003] Internally threaded, plastic cap closures have found
widespread application for use in connection with hot-fill plastic
containers by virtue of their low manufacturing costs and sealing
performance. In a conventional hot-fill process, a hot beverage
product is introduced into the plastic container, typically filling
most of the container. The fluid is heated during a pasteurization
or sterilization process to remove bacteria or other contamination.
The plastic container is hermetically sealed with a cap while the
product is still hot. Since the beverage product is typically not
filled to the top of the container, a headspace of air is provided
between the liquid enclosed within the plastic container and an
inner surface of the cap. The temperature of the liquid varies from
a high of about 185 degrees Fahrenheit, the typical hot-fill
temperature, to about 40 degrees Fahrenheit, the typical
refrigeration temperature. A change in temperature, from hot to
cold, decreases the internal pressure of the sealed container and
creates a vacuum within the container primarily as a result of the
thermal contraction of the liquid in the container. This decrease
in pressure can distort and/or deform the geometry of the container
if the container cannot structurally support the pressure
difference between the external ambient pressure and the lower
internal pressure of the container. Deformation of the container
generally pushes the fluid upwardly and decreases the headspace
volume. For example, for a typical 16-ounce container, thermal
contraction equates to roughly 3% of the total liquid volume, or
0.9 cubic inches when the stored contents are cooled from about
185.degree. to about 40.degree. F.
[0004] Current containers are engineered to collapse at specific
locations or are reinforced with vacuum panels and/or flexible
bases to compensate for the vacuum. Vacuum-reactive mechanisms are
very efficient to maintain a balanced pressure and keep the
remaining structural geometry of the container from collapsing.
Vacuum panels, however, are difficult to mold. Further, labeling of
the container is difficult because containers employing raised
and/or recessed vacuum panels possess reduced surface area. The
reduction of surface area also restricts the ornamental design of
the label, restricts the placement of the label, and often leads to
unattractive wrinkling of the label.
[0005] Embodiments of the present invention described herein are
directed to an apparatus and method for accommodating the pressure
decrease associated with hot filling and subsequently cooling a
liquid stored in a plastic container. By addressing the vacuum
created within the container, vacuum panels may be eliminated or
reduced.
SUMMARY OF THE INVENTION
[0006] Accordingly, it is one aspect of the present invention to
provide a method and apparatus for accommodating a pressure change
in a plastic bottle that occurs during hot-filling, capping, and
subsequently cooling a beverage container. In one embodiment of the
present invention a plastic closure cap for containers is provided
that define a headspace. When the container and beverage is cooled,
the headspace air pressure reduces to a level less than the
external pressure felt by the container, i.e., a vacuum is created.
A diaphragm is associated with the cap to eliminate or
significantly reduce the vacuum in the container. Thus, the
container is able to accommodate any pressure differential between
the external pressure and the reduced pressure in the container
without substantially deforming.
[0007] It is another aspect of the embodiments of the present
invention to provide a closure cap having one or more sealing
features associated with the cap. When the cap is positioned on a
container neck, the sealing features hermetically seal the cap to
the container. As the cap is tightened onto the neck of the
container, the sealing mechanism is driven downward and
simultaneously compresses the air in the headspace. The increase in
pressure is sufficient to compensate the reduction in pressure that
occurs when the container is cooled. Distortions generally
associated with the pressure decrease are thus avoided.
[0008] In another aspect of embodiments of the present invention to
provide a plastic cap having a "slider ring" is positioned within
an annular void within the cap. The slider ring can be a polymeric
material having oxygen barrier properties, such as, but not limited
to polypropylene, thermoplastic elastomers (TPE), or co-polymers
thereof. The slider ring also may include one or more sealing
features, such as a cylindrical or semi-cylindrical circumferential
features. When the cap is positioned on a container neck, the
slider ring hermetically seals the cap to the container, and
creates a seal between the cap and the internal surface of the neck
of the container. Air within the container is prevented from
escaping as the cap is tightened onto the container neck which
pressurizes the trapped air in the headspace. The pressure increase
is designed to accommodate the pressure decrease experienced during
cooling of the stored contents, thus eliminating or significantly
reducing any pressure drop or vacuum in the container.
[0009] It is yet another aspect of embodiments of the present
invention is to provide a plastic cap closure having a flexible
bellows. The flexible bellows extend within the neck of the
container to reduce or eliminate the vacuum. During attachment of
the closure to the neck of the container, the bellows is compressed
to force air positioned therein into the container which creates a
pressure increase within the container. The pressure increase is
sufficiently large such that when the container is cooled, a
pressure decrease sufficient enough to distort the container will
not form.
[0010] Still yet another aspects of embodiments of the present
invention is to provide a closure cap having one or more sealing
features within the cap and/or a method of applying the cap to a
container which limits the head pressure during the sealing
process. More specifically, when sealed under excessive pressure,
the container can expand and/or reform. Thus, one embodiment of the
present invention reduces the headspace pressure to substantially
prevent bursting of the container. An optimal headspace pressure is
contemplated that is less than the burst pressure of the container
and less than the container distortion pressure. For example, the
closure cap may at least partially vent the air entrained in the
headspace to maintain the optimal headspace pressure, or can
alternatively vent during removal of the cap to allow easier
removal of the cap from the container. Alternatively, the capping
process can be conducted to achieve the optimal pressure, as for
example, by capping at an optimally preferred temperature and/or
with an optimally preferred headspace volume.
[0011] It is yet another aspect of embodiments of the present
invention to employ a movable diaphragm that accommodates the
pressure decrease. The diaphragm includes a head that transitions
from a first position of use, adjacent to an inner surface of the
cap, to a second position of use, within the neck of the container,
to compensate any pressure decrease or increase. In order to allow
for the head of the diaphragm to move downwardly, air is
communicated from outside the container into a space between the
head of the diaphragm and the inner surface of the cap. The air is
prevented from contacting the contents of the container by a
non-permeable portion of the diaphragm. When the cap is removed
from the container, the head of the diaphragm, preferably,
transitions automatically upwardly to engage the inner surface of
the cap.
[0012] It is still yet another aspect of the present invention to
provide a container that is easy to label or add indicia thereto.
By omitting the need for vacuum panels, embodiments of the present
invention provide greater label contact area. The containers, thus,
are designed to be more distinctive in shape without requiring
about 50% of the visible surface area being dedicated to vacuum
panels. Furthermore, containers of the present invention are
designed around structural integrity instead of collapse, thus
resulting in lighter bottles and material savings.
[0013] Although these aspects of the invention have been described
separately, one of skill in the art will appreciate that some or
all variations of the inventions may be combined. Further, the
Summary of the Invention is neither intended not should be
construed as being representative of the full extent and scope of
the present invention. The present invention is set forth in
various levels of detail in the Summary of the Invention and as
well in the attached drawings and in the detailed description of
the invention and not limitation as to the scope of the present
invention is intended by either the inclusion or non-inclusion of
elements, components, etc. in this Summary of the Invention.
Additional aspects of the present invention will be come more
readily apparent from the Detailed Description, preferably when
taken together with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 depicts one embodiment of the present invention that
utilizes a sealing slider ring wherein a cap is shown initially
engaged on a container neck;
[0015] FIG. 2 shows the embodiment of FIG. 1 wherein the cap is
shown fully interconnected to the container neck;
[0016] FIG. 3 is a detailed view of FIG. 2;
[0017] FIG. 4 depicts another embodiment of the present invention
that utilizes a bellows shown initially contacts the container
neck;
[0018] FIG. 5 shows the embodiment of FIG. 4 wherein the cap is
shown fully interconnected to the container neck;
[0019] FIG. 6 is a partial cross-sectional view of the cap of
another embodiment of the present invention shown positioned on a
container neck prior to sealing;
[0020] FIG. 7 is a partial cross-sectional view of the cap shown in
FIG. 6 fully interconnected to a container neck;
[0021] FIG. 8 is a bottom perspective view of a cap of another
embodiment of the present invention that employs a selectively
deflectable diaphragm;
[0022] FIG. 9 is a cross-sectional perspective view of the cap
shown in FIG. 8 wherein the diaphragm has been omitted for
clarity;
[0023] FIG. 10 is a cross-sectional perspective view of the
diaphragm shown in FIG. 8;
[0024] FIG. 11 is a front elevation view of the cap of FIG. 8 shown
initially engaged on a container neck;
[0025] FIG. 12 is a front cross-section of FIG. 11, wherein the
diaphragm is shown positioned in a first position of use;
[0026] FIG. 13 is a perspective view of FIG. 12;
[0027] FIG. 14 is a front elevation view of the cap of FIG. 8 shown
completely sealed onto a container neck;
[0028] FIG. 15 is a front cross-section of FIG. 14, wherein the
diaphragm is shown positioned in a first position of use;
[0029] FIG. 16 is a perspective view of FIG. 15;
[0030] FIG. 17 is a front elevation view of the cap of FIG. 8 shown
completely interconnected to the container neck;
[0031] FIG. 18 is a cross-sectional view of FIG. 17 wherein the
diaphragm is shown in a second position of use, thereby
accommodating a pressure decrease in the sealed container;
[0032] FIG. 19 is a perspective view of FIG. 18;
[0033] FIG. 20 is a front elevation view of the cap shown in FIG. 8
shown removed from the container neck; and
[0034] FIG. 21 is a cross-sectional view of FIG. 20 wherein the
diaphragm has rebounded to its first position of use.
[0035] To assist in the understanding of the present invention the
following list of components and associated numbering found in the
drawings is provided herein:
TABLE-US-00001 # Component 2 Container neck 6 Cap 10 Slider ring 14
Inner surface 18 Inner surface of the neck 22 Interior portion 26
Bellows 30 Sealing mechanism 34 Headspace 38 Container outer
surface 42 Container top surface 46 Container thread 100 Closure
102 Closure Upper End 104 Skirt Portion of Closure 110 First seal
element 112 Second seal element 114 Seal Retention Feature 116 Seal
Retention Leg 118 Seal Retention Arm 120 Upper Surface of Seal
Retention Arm 122 Lower Surface of Seal Retention Arm 124 Retaining
Lip 126 Closure Internal Thread System 128 Closure Skirt Projection
130 Inner Top Surface of Closure 132 Inner Skirt Surface of Closure
134 Lower End of Seal Retention Leg 136 First Sealing Groove 138
Second Sealing Groove 140 First Seal 142 Second Seal 144 Fully
Seated Closure Position 146 First Side of Retention Leg 148 Second
Side of Retention Leg 300 Cap 304 Diaphragm 308 Side wall 312 Main
panel 316 Inner surface 320 Fin 324 Head portion 328 Threads 332
Threads 336 T/E band 340 Bridge 344 T/E catch 348 Grip 352 Gap 356
Upper catch 360 Lower catch 364 Inner skirt 368 Outer skirt 372
Convolution 376 Seal 380 Catch ring 384 Vent 388 Rebound disk 392
Neck 396 Inner portion 400 Inclined surface 404 Air
[0036] It should be understood that the drawings are not
necessarily to scale. In certain instances, details that are not
necessary for an understanding of the invention or that render
other details difficult to perceive may have been omitted. It
should be understood, of course, that the invention is not
necessarily limited to the particular embodiments illustrated
herein.
DETAILED DESCRIPTION
[0037] Referring now to the drawings, FIGS. 1-3 depict a closing
sequence for one embodiment of the present invention. More
specifically, a neck 2 of a plastic bottle is shown with a threaded
cap 6 positioned on an uppermost portion. A sealing ring 10 that
seals the cap 6 to the neck 2 during the closing sequence is also
shown. In operation, the cap 6 is placed on the neck portion 2 of
the container after the container is hot-filled with a beverage. A
seal is created by the sealing ring 10 to prevent the escape of gas
located between the fluid and the inner surface 14 of the threaded
cap 6. As the cap 6 is rotated, the air between the inner surface
14 and the fluid (i.e., headspace) is pressurized. The seal formed
between the interior 18 of the neck 2 of the container and the
sealing ring 10 positioned on the interior portion 22, or fin of
the cap 6. As the cap 6 is screwed downward, the seal between the
neck 2 and the cap 6 prevents any gas from escaping, and a positive
pressure is created within the headspace of the container.
[0038] Referring now to FIGS. 4 and 5, a pressure compensating
member in the form of a bellows 26 is shown. More specifically, the
neck 2 of a plastic bottle is shown with the threaded cap 6
positioned on an uppermost portion. The cap 6 includes a bellows
system 26 with a sealing mechanism 30 at one end thereof. In
operation, the cap 6 is placed on the neck portion 2 of the
container after the container is hot-filled with a beverage. Upon
contact the seal 30 is created that prevents the escape of gas
located in the headspace 34. As the cap 6 is rotated, the bellows
26 is compressed and forces the air therein into the headspace 34.
The seal 30 is formed between the interior of the neck 2 of the
container and the bellows 26 positioned on one end of the bellows
26. As the cap is screwed onto the neck 2, the seal 30 between the
neck 2 and the bellows 26 prevents any gas from escaping, and a
positive pressure is created within the headspace 34.
[0039] Referring now to FIGS. 6 and 7, a threaded cap 100
representing another embodiment of the present invention is shown.
More specifically, the cap 100 is comprised of an upper end 102
with a skirt portion 104 extending therefrom, and may include an
anti-pilfer band interconnected to the skirt 104 by a score line.
The cap 100 is may be comprised of a plastic material, preferably,
an injection moldable thermoplastic plastic material having oxygen
barrier properties. Alternatively, the cap may be comprised of
metallic materials or a combination thereof.
[0040] A seal retention feature 114 positioned substantially
concentrically within the plastic closure cap 100, and held within
the cap 100 by a retaining lip 124 and a closure upper end 102. In
one embodiment, the seal retention feature 114 includes a seal
retention arm 118 and a seal retention leg 116. The seal retention
leg 116 has a lower end 134, a first side 146 and opposing second
sides 148. The seal retention arm 118 has an upper surface 120 and
lower surface which generally oppose each other. The seal retention
arm 118 and seal retention leg 116 can be separate and distinct
elements which are joined together to form the seal retention
feature 114, or the seal retention arm 118 and leg 116 leg can be
elements of the seal retention feature 114. In one embodiment, the
cross-section of the retention feature 114 can resemble an inverted
letter "L". The retention feature 114 can be any polymeric
material, preferably, a plastic material capable of being injected
molded. More preferably, the polymeric material is a thermal
plastic having oxygen barrier properties, or a material having
thermoplastic properties, that can be injected molded.
[0041] In a one embodiment, first 110 and second seal elements 112
are operably interconnected to the retention feature 114. The first
seal element 110 is positioned in a first seating groove 136 on the
retention leg 116 between an inner skirt surface 132 and the
retention leg 116. Preferably, the first seal element 110 is
positioned nearer the lower end 134 of the seal retention leg 134
than the lower surface 122 of seal retention arm 118. The second
seal element 112 is positioned in second seating groove 138 on the
retention arm 118 between the inner top surface 130 and the
retention arm 118. Preferably, the second seal element 112 is
positioned nearer the retention leg 116 than the inner skirt
surface 132.
[0042] In a preferred embodiment, the first seal element 110 and
second seal element 112 are o-rings or other similar sealing
devices well known in the art. More specifically the o-ring
described herein is generally an elastomeric seal or gasket loop,
with any variety of geometries and cross-sections which are
designed to be seated in a groove and compressed between two or
more parts to form a seal. The seal is maintained as long as the
contact pressure of the o-ring exceeds the pressure being
maintained by the o-ring. More specifically, the term "sealing
device" generally means any compression fit device, wherein
pressure cannot escape between the interior of the container and
the cap seal.
[0043] The first seal element 110 and second seal element 112 are
selected based on one or more of: chemical compatibility (with, for
example, the plastic hot-fill container, the hot fill product, any
lubricants, any adhesives, and any associated gases), temperature
(such as, but not limited to, closure manufacturing, hot fill,
post-fill, retail, and consumer-use temperatures), sealing pressure
(that is, the pressure to form and maintain the seal), lubrication
requirements (for the seal to slide along the container), food
safety requirements (for example, governmental, agency, trade, and
corporate), and cost.
[0044] The first seal element 110 and second seal element 112 can
be any suitable thermoplastic polymer, thermoset rubber, or
co-polymer or mixture thereof. Preferred thermoplastic polymers are
generally: elastomer (TPE) styrenics; polyolefins (TPO), low
density polyethylene (LDPE), high-density polyethylene (HDPE),
linear low-density polyethylene (LLDPE), ultra low-density
polyethylene (ULDPE); polyurethanes (TPU) polyethers and
polyesters; etheresterelastomers (TEEEs) copolyesters; polyamides
(PEBA); melt processible rubbers (MPR); vulcanizates (TPV); and
mixtures and/or co-polymers thereof. Preferred thermoset rubbers
are generally: butadiene rubber (BR); butyl rubber (IIR or PIB);
chlorosulfonated polyethylene (CSM); epichlorohydrin rubber (ECH or
ECO); ethylene propylene diene monomer (EPDM); ethylene propylene
rubber (EPR); floroelastomers (FKM); nitrile rubber (NBR);
perfluoroelastomer (FFKM); polyacrylate rubber (ASM);
polycholorprene (CR); polyisoprene (IR); polysulfide rubber (PSR);
silicon rubber (SiR); styrene butadiene rubber (SBR); and mixture
and/or co-polymers thereof.
[0045] FIG. 6 depicts a neck of an associated container 2 which is
filled with a hot-filled product wherein the cap 100 is initially
positioned on the neck of the container. The neck 2 has opposing
inner 18 and outer 38 surfaces, a top surface 42, and thread system
46. As shown, the closure cap 100 is positioned on the hot-fill
container 2 prior to engagement of the closure cap 100 internal
thread 126 and container threads (not shown). Prior to positioning
the closure cap 100 on the container 2, the second sealing feature
112 is not in contact with the inner top surface 130.
[0046] After positioning the cap 100 on the neck of the container
2, a downward pressure is applied to the closure cap 100 to form a
first seal 140 between the first seal element 110 and the inner
surface 18. Likewise, the applied pressure forms a second seal 142
between the second seal element 112 and the inner top surface 130.
One or more of the first 140 and second 142 seals creates a first
headspace volume and first headspace pressure by hermetically
sealing the closure 100 to the container 2.
[0047] Following or occurring about simultaneously with the
formation of the first 140 and second 142 seals, the internal
thread 126 and thread 46 systems are engaged by rotating the cap
100. As the rotation continues, the inner surface 130 advances
towards container top surface 42, decreasing the headspace volume.
Decreasing the headspace volume increases the headspace pressure
within container 2 (which can be understood and calculated by one
or more of the gas laws of Charles, Boyle and Gay-Lussac).
[0048] The closure cap 100 is rotated until the closure cap 100 is
fully seated on the container 2, fully sealing the container 2 as
depicted in FIG. 7. In the fully seated position 144, the upper
surface 120 is adjacent to the inner top surface 130 and the top
surface 42 is adjacent to the lower surface 122. The fully sealed
container has a second headspace volume significantly less than the
first headspace volume and a second headspace pressure
significantly greater than the first headspace pressure. The fully
sealed container can experience a variety of temperatures during
storage, shipment, retail displace, and consumer-use. Typically,
the minimum temperature experienced is about 40 degrees Fahrenheit,
when the sealed container is refrigerated.
[0049] It should be appreciated that any temperature change may
affect the headspace pressure and a reduction in temperature will
decrease the headspace pressure. When the headspace pressure
decreases sufficiently to create a vacuum, the hot-fill plastic
container can distort. The distortions can be obviated by having
the seating of cap 100 on the container 2 generate a sufficiently
large headspace pressure to compensate for the decrease in
headspace pressure when the container 2 is refrigerated. Thus, the
headspace pressure within container 2 is sufficiently large that
any decrease of the headspace pressure during cooling or
refrigeration will not distort the structural geometric integrity
of the plastic container. Thus, a headspace pressure can be
generated which is sufficiently large that the container need not
have reinforced panels and/or a flexible base to resist distortion
during cooling. It is further appreciated that, the second
headspace pressure needed to avoid container distortions can be
calculated by the ideal gas law (or gas laws of Charles, Boyle,
and/or Gay-Lassac).
[0050] As appreciated by one skilled in the art, the headspace
pressure may be altered by at least one or more of the following:
the degree to which the container is filled; the initial headspace
temperature; the diameter and height of the cap; the dimensions and
shape of the container; the physical properties of the container;
the physical properties of the material comprising the container;
the dimensions and shape of the container neck; the placement of
the sealing features (or slider) within the cap; the lowest
temperature the sealed container is exposed to and the composition
of the gas and/or liquid in the container or headspace.
[0051] When the cap 100 is rotated to remove the cap from the
container, the retention feature 114 contacts the retention lip 124
separating the second seal element 112 and inner top surface 130,
creating a void volume between element 112 and surface 130. That
is, the second seal element 112 and inner top surface 130 are no
longer in contact and the second seal 142 no longer exists. When
the seal breaks, the cap can subsequently be removed with a
reduction in force. Likewise, in the closure removal process, the
first seal element 110 and the inner surface 18 are separated by a
void and the first seal 140 no longer exists.
[0052] Referring now to FIGS. 8-21, yet another embodiment of a cap
300 is shown that employs a selectively deformable diaphragm 304.
The cap 300 also includes a sidewall 308 that depends from a main
panel 312. The main panel 312 has an inner surface 316 with a
plurality of fins 320 extending therefrom. In one embodiment of the
present invention a resiliently deflectable diaphragm 304 is
positioned such that in a first position of use a head portion 324
thereof rests against the inner surface 316 of the cap 300. In a
second position of use the head portion 324 is positioned in a
lower position in a direction toward the stored fluid.
[0053] Referring now to FIG. 9, a cross-sectional view of the cap
300 is shown that comprises the main panel 312 with sidewall 308
extending therefrom. The sidewall 308 includes internally disposed
threads 328 for selective engagement with threads 332 of a
container neck (see FIG. 17, for example). The sidewall 308 also
includes the position for attachment of a tamper evidence ("T/E")
band 336 (e.g., Pilfer Proof) via a bridge 340. The T/E band 336 is
used as a visual indicator that the cap has been loosened from the
neck. The T/E band 336 also includes a T/E catch 344 that maintains
the T/E band 336 on the container neck after the cap 300 is removed
or twisted such that one or more of the bridge members 340 break.
In order to facilitate twisting of the cap 300 the sidewall 308 may
include a plurality of gripping members 348. Extending from the
inner surface 316 of the cap are the plurality of fins 320 that are
spaced such that gaps 352 are provided therebetween. The fins 320
also include, in one embodiment of the present invention, an upper
catch 356 and a lower catch 360 that selectively position the
diaphragm which will be described in further detail below.
[0054] Referring now to FIG. 10, the diaphragm 304 of one
embodiment of the present invention is shown. Preferably, the
diaphragm 304 is a shaped piece of resiliently deflectable material
such as polyethylene, polypropylene, or other similar plastic
materials. One skilled in the art, however, will appreciate that
other flexible materials can be used without departing from the
scope of the invention. The diaphragm 304 includes an inner skirt
364 positioned inwardly from an outer skirt 368 with a convolution
372 therebetween. The outer skirt 368 includes a flange or sealing
surface 376 interconnected thereto. A catch ring 380 is either
integrally molded onto the seal 376 and/or outer skirt 368 or
interconnected to the seal 376. The catch ring 380 employs at least
one vent 384 to allow air to pass from a location beyond an outer
surface of the seal 376 to a position between the inner skirt 364
and the outer skirt 368. Preferably, the diaphragm 304 has a
generally flat head portion 324 that is pulled downwardly when the
pressure of the fluids stored within the sealed container
decreases. In one embodiment of the present invention a rebound
disk 388 (or ring) is generally interconnected to the head portion
324 of the diaphragm 304 that is generally rigid and facilitates
movement of the head to its upward position when the sealed
container is open.
[0055] Referring now to FIGS. 11-13, the cap 300 of the present
invention with a diaphragm 304 is shown interconnected to the neck
392 of a container. As illustrated, the seal 376 is engaged to a
top portion of the neck 392. In FIG. 11, the cap 300 is shown prior
to tightening onto the neck 392. Prior to tightening, the seal 376
is placed onto the top portion of the neck 392 wherein the seal 376
is positioned between the catch ring 380 and the neck 392. The
rebound disk 388 of the embodiment shown is positioned against an
inner surface 316 of the cap 300. As the cap 300 is rotated, the
threads 328 of the cap will come in contact with the threads 332 of
the neck 392 to transition the cap 300 downwardly onto the neck
392. Rotating the cap will move the fin 320 downwardly to contact
the convolution 372 of the diaphragm 304. Further, as the cap is
rotated a "pre-pressure", or air volume is added to the headspace
of the container. Thus, the headspace pressure can be increased
during the closure of the container as the cap is screwed to the
neck of the container.
[0056] FIGS. 14-19 illustrate the cap 300 sealingly engaged on the
container neck 392 with the heated liquid therein. FIGS. 14-16 show
the cap 300 completely tightened onto the container neck 392
wherein the diaphragm 304 is in a first position of use prior to
the cooling of the liquid product. FIGS. 17-19 shows the affect of
content cooling on the diaphragm 304. To seal the container, the
cap 300 is placed on the neck 392 such that the seal 376 rests on
the upper end of the container neck 392. The catch ring 380, which
is integrated or otherwise affixed to the seal 376 is also
positioned over the upper surface of the container neck 392. As the
cap 300 is rotated onto the container neck 392, the fins 320 will
transition downwardly to contact the convolution 372 of the
diaphragm 304. As this happens, the upper catch 356 of the fin 320
will deflect an inner portion 396 of the catch ring 380 and
transition thereby. More specifically, the upper catch ring 380
includes an inclined surface 400 that facilitates the upper catch
ring's 380 transitions past the inner portion 396 of the catch ring
380. Thereafter, the catch ring 380 is prevented from moving
relative to the main panel 312 of the cap 300, and is maintained
relative thereto.
[0057] Referring now to FIGS. 20 and 21, in operation the diaphragm
304 is designed to transition downwardly when the stored product in
the container cools. In order to facilitate this downward motion,
air from the external environment travels through the threads of
the neck 332, through the vents 384 in the catch ring 380 and
through the gaps 352 of the fins 320. This air 404 enters a space
between the main panel 312 of the cap and the head of the diaphragm
304, provided by the pressure drop, thereby equalizing the pressure
inside and outside the container. As one skilled in the art will
appreciate, if the contents of the container should subsequently
heat up, the pressure of the stored fluids within the container
will increase and force the diaphragm 304 upwardly, thereby
transitioning air from between the space through the gaps 352 in
the fins, through the catch ring vents 384 and subsequently through
the threads. The transfer of air into the container is more
commonly seen when the cap 300 is removed from the container.
[0058] More specifically, the cap 300 is rotated in a direction
opposite from tightening. As the cap 300 is rotated, the catch ring
380 and associated seal 376 are pulled away from the upper surface
of the neck 392, which allows any pressure differential or vacuum
within the container to be quickly equalized. The pressure
equalization removes the force that pulls the diaphragm 304
downwardly as seen in FIGS. 18 and 19. The diaphragm 304 is then
able to return to its first position of use as shown in FIG. 12. In
order to facilitate this return, a rebound disk 388 that is
interconnected to the head portion 324 of the diaphragm 304 is
provided. The rebound disk 388 is made of a stiffened material that
is radially loaded by an inner wall of the diaphragm 304 when it is
pulled downwardly. The rebound disk 388 also keeps the head of the
diaphragm 304 substantially planar to allow for even pressure
distribution across the same. When the pressure differential is
removed, the potential energy stored within the rebound disk 388 is
released to aid the resilient nature of the diaphragm 304 to return
it to its first position. Also note that the catch ring 380 and
seal 376 after removal of the cap 300 remains adjacent to the inner
surface 316 thereof.
[0059] The foregoing discussion of the invention has been presented
for purposes of illustration and description. The foregoing is not
intended to limit the invention to the form or forms disclosed
herein. Although the description of the invention has included
description of one or more embodiments and certain variations and
modifications, other variations and modifications are within the
scope of the invention, e.g., as may be within the skill and
knowledge of those in the art, after understanding the present
disclosure. It is intended to obtain rights which include
alternative embodiments to the extent permitted, including
alternate, interchangeable and/or equivalent structures, functions,
ranges or steps to those claimed, whether or not such alternate,
interchangeable and/or equivalent structures, functions, ranges or
steps are disclosed herein, and without intending to publicly
dedicate any patentable subject matter.
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